Tools and Materials for Building an AR
Short Story: You cannot build an AR without a minimal set tools. You cannot build an AR properly without the appropriate tools and lubrication.
If you are starting from scratch, you are looking at a minimum $500-600 investment for the necessary tools and materials. But it is an investment that will give you the capability to maintain and repair your firearm, as well as build as many of these as you want. After all, you typically only need to buy a tool once. (WARNING: building ARs is addictive…the cost of DIY can balloon very quickly 😉)
R: Required
r: Recommended
O: Optional
Slick Stuff (Lubrication)
Check out the Lock and Lube page for details about how to use lubricants.
Grease
There are a few places on the AR that should get grease, and we only use it during assembly. Grease is used for two primary purposes in building an AR: 1) to lubricate threads (this ensures that all applied torque transfers to thread mating, rather than to overcoming friction), and 2) to avoid galvanic corrosion where two dissimilar metals are otherwise in contact. We use two types of grease.
High Temp Grease: AeroShell 64
AeroShell 64 is a superb all around high temperature grease that can be used in most places on the AR platform. We use AeroShell to lubricate the following:
- Barrel Extension
- Barrel Nut/Upper Receiver Threads
- Receiver Extension Threads
In a pinch, AeroShell can be used to lubricate the muzzle threads (as applicable to the muzzle device). However, AeroShell is not the best option due to the extreme temperatures experienced at this location.
Ultra-High Temp Grease: Molykote G-Rapid Plus Paste
Molykote G-Rapid Plus Paste is an ultra-high temp anti-seize grease. The upper operating temperature limit is substantially higher than AeroShell 64. For comparison, the upper limit for AeroShell 64 is 121°C (250°F); the upper limit for Molykote is 450°C (842°F).
Molykote can technically be used anywhere on the AR platform, but is overkill in most places. We only use Molykote for lubricating the muzzle threads (which is a very high heat location) when installing a muzzle device that uses either a crush washer or a lock nut.
Wet Lubricant
Wet lubricant is used for all moving parts, during assembly and for routine lubrication. In general, lubricants should balance the viscosity between thin enough to stay fluid in cold weather and thick enough to stay put. We primarily use two types of lubricant, but a third can be used as well. A word of caution: do not mix lubricants (i.e. don’t switch back and forth between lubricants).
Light Wet Lubricant: Mobil 1 Synthetic Motor Oil (0W20 or 0W30)
We use synthetic motor oil as our standard lubricant. It is engineered for some of the toughest environmental conditions and does very well as a general gun lube.
Heavy Wet Lubricant: Mobil 1 Oil/Grease Blend
We use a custom blend of light synthetic motor oil and synthetic grease (1 part grease to 5 parts oil) in high wear locations (e.g. the bolt and cam pin shaft). We mix this using a dedicated immersion blender to achieve homogeneity.
Clean-Lubricate-Protect (CLP): Clenzoil Field and Range
We don’t generally use CLP because it doesn’t stay put and requires frequent reapplication. For this reason, it is also not a good long term storage lubricant. However, if you use your gun frequently and can reapply as needed, CLP is a great option as a general lubricant. CLP is very effective at preventing friction/wear and has the added benefit of making cleanup a breeze. We recommend Clenzoil Field and Range CLP (refer to THIS VIDEO for objective performance testing).
Application Tools
There are a couple of tools that we use for applying lubricants.
Needle Bottle
A needle bottle is the ideal tool for applying your general wet lubricant. You can apply lubricant precisely where you need it, including in detent cavities and in tight, hard-to-reach locations. A needle bottle will also help avoid over-lubrication.
Dropper Bottle
We use a dropper bottle for applying larger amounts of general wet lube, and for our custom oil-grease blend.
Solvent Pump Bottle
We apply oil with our fingers all the time. We use a solvent/alcohol pump bottle to make wetting our fingers with oil fast and easy.
Finger Cots
We apply grease very frequently. We use finger cots to make cleanup fast and easy.
Sticky Stuff (Thread Locker)
Thread locker must be used carefully and strategically. If you don’t know what not to use it on, don’t use it at all. Please PLEASE read the Lock and Lube page before you apply any type of thread locker to any part of your AR.
We do not recommend “bedding” your barrel extension with thread locker or “retaining compound” (i.e. Loctite 620), especially if you don’t know what you are doing (we’ve seen armorers ruin upper receivers by attempting this).
We recommend two types of thread locker for the AR.
Thread Locker (Hardening): Flexbar Rocksett/Rocksett Muzzle Adhesive
The only type of hardening thread locker you should use on the AR for locking threads is Flexbar Rocksett. It is a ceramic cement that is heat resistant up to 1,102°C (2,015°F). For reference, Loctite 243 (blue) is resistant up to 150°C (302°F); Loctite 272 (red) is resistant up to 232°C (450°F). Rocksett can be used everywhere on the AR, including all the places where Loctite would turn to dust.
Note that Rocksett and Rocksett Muzzle Adhesive are the same product. Rocksett Muzzle Adhesive comes in smaller 1 oz bottle versus the larger 2 or 4 oz bottle for the Rocksett-labeled product. 1 ounce will last for many applications, so this is probably more than enough for most folks.
Thread Locker (Non-Hardening): Vibra-Tite VC3
For all the places you shouldn’t use hardening thread locker but need some added assurance, we use Vibra-Tite VC3 threadmate. VC3 is like liquid rubber that cures to a flexible coating. There is no risk of damaging threads and no need to heat the compound to loosen a screw. We use VC3 on handguard screws. It can also be used for pistol grip screw and sight/scope mount screws.
Tools For Leverage (Wrenches)
* Muzzle devices may require specific torque (refer to the muzzle device manufacturer’s instructions) and therefore, the wrench should be compatible with your torque wrench. If you are using a crush washer, you can probably get away without a torque wrench, though it is strongly recommended to ensure minimal holding and to prevent constriction of the bore. If you choose to not use a purpose-built wrench, we recommend a fixed crescent wrench versus an adjustable wrench to avoid damaging the the muzzle device. Check the specifications of your muzzle device for the need for a wrench and, if so, the span of the wrench flats. Be aware that some muzzle devices include a spanner wrench (e.g. Precision Armament Hypertap Muzzle Brake). The 5/8″ wrench that we like is compatible with muzzle devices that have 5/8″ wrench flats (common for 1/2-28 muzzle devices). Similarly, the 3/4″ wrench is compatible with muzzle devices that have 3/4″ wrench flats (common for 5/8-24 muzzle devices).
** If you are using an armorer’s wrench in place of any other wrench, be sure the wrench has a 1/2″ socket for a torque wrench. Consult our Torque Adjustment page for instructions on calculating the adjusted torque setting for your tool.
Tools You Twist (Drivers and Bits)
* Only required for installing the buttstock mounting screw for rifles.
Tools You Whack (Punches)
1: Generally not required unless you buy the BCG unassembled or need to replace the ejector.
2: Not required for Aero Precision Enhanced Lower Receivers, which have a threaded screw in place of the roll pin. Anyone who has attempted to seat a bolt catch roll pin for the first time can tell you (and probably show you via the marred lower receiver) how much of a blessing this feature is.
3: Not required for Aero Precision Enhanced Upper Receivers, which have a threaded screw in place of the roll pin.
4: Not required for Aero Precision Enhanced Lower Receivers, which have the trigger guard forged onto the lower receiver.
Tools You Swing (Hammers and Mallets)
1: Brass is best, but any metal head will work. We recommend something 8oz or less.
Tools That Hold Stuff (Blocks and Vices)
1: The jaws of the vice block must be wide enough to accommodate the vice block. A 3″ jaw opening is sufficient for the vice block models that we recommend.
2: The Vism vice block works with the Aero Precision AR-10 (M5) platform. However, because the AR-10/LR308 platform is not standardized, lowers from some manufacturers may not be compatible.
3: Note that this tool is NOT COMPATIBLE WITH AR-10 components.
4: Note that this tool is NOT COMPATIBLE WITH AR-15 RECEIVERS.
5: We have tried a few gas block jigs and have yet to find any that fit a wide range of gas blocks without modification. We have exhausted our retail options, so we are getting ready to try out some options available on Etsy and will report back soon.
Tools We Didn’t Categorize (Other Installation Tools)
1: Poor gas block alignment will cause cycling and reliability issues.
2: This tool is priceless. It will save you a lot on lost detents and eye surgery.
3: We do NOT recommend using clamp on gas blocks. They are too susceptible to shifting on the barrel, which will cause cycling issues.
3: Note that this tool is NOT COMPATIBLE WITH AR-10 components.
4: Note that this tool is NOT COMPATIBLE WITH AR-15 components.